Process for preparing 3-pentene nitrile

ABSTRACT

3-PENTENE-NITRILE IS PREPARED BY ISOMERIZATION OF 2-METHYL-3BUTENE-NITRILE, USING A NICKEL COMPLEX AS CATALYST.

United States Patent 1151 3,697,578 Pasquino et al. 51 Oct. 10, 1972[54] PROCESS FOR PREPARING 3- [56] References Cited PENTENE NITRILEUNITED STATES PATENTS [72] Inventors: Pietro Pasquino, Vercelli; Luigi 3537 748 10/1970 D k d J t 1 260/465 9 Benzoni, Novara; Giuseppe Camisio,l at e ni Colombo, a, Dnnkard, J1. et f 0 Italy 3,542,847 11/1970Drinkard, Jr. et a]. .260/465.9 [73] Assignee: Montecatini EdisonS.p.A,, Milan, 3,551,474 12/1970 Drinkard, Jr. et al. .260/465.9 Italy3,564,040 2/1971 Downing et a1.....260/465.3 X [22] Filed: 16, 19703,579,560 5/1971 Dnnkard, Jr. et a1. .260/465.9

[21] Appl. No.: 98,908 Primary ExaminerJoseph P. Brust Attorney-PatriciaQ. Peake and Stevens, Davis, [30] Foreign Application Priority DataMiner & Mosher Dec. 17, 1969 Italy ..25901 A/69 [57] ABSTRACT3-pentene-nitrile is prepared by isomerization' of 2- [52] US. Cl..260/465.9 methyl 3 butene nimle, using a nickel complex as [51] Int.Cl ..C07c 121/30 catalyst [58] Field of Search ..260/465 .9

3 Claims, No Drawings PROCESS FOR PREPARING 3-PENTENE NITRILE Accordingto the invention, the isomerization of the 2-methyl-3-butene-nitrile isaccomplished by heating it at a temperature of from 50 C to 150 C, inabsence of a solvent, at normal pressure, for a time period ranging from15 to 150 minutes, and in the presence of a catalyst consisting of aphosphinic complex of nickel.

The 2-methyl-3-butene-nitrile used as starting material may be obtained,for example, as by-product of the reaction between hydrocyanic acid andbutadiene, for the preparation of linear, unsaturated nitriles.

The unsaturated nitriles are useful as intermediates in the preparationof amines, dinitriles, and acids. Thus, 3-pentene-nitrile may betransfonned, by the addition of HCN, into adiponitrile which is a usefulintermediate in the production of nylon.

The nickel complexes used as catalysts in the process of the inventioncorrespond to the following formula where Ph represents the phenyl groupand n represents a whole number and is 3, 4 or 5.

Phosphinic nickel complexes comprised within the formula include n=3Ni[Ph P-(C1-l PPh which is di[1,3-bis(diphenylphosphine)-propane]nickel, and hereinafter indicated asNi(dp-pr) n 4 Ni[Ph P-(C1-l -PPh which is di[ 1,4-bis(diphenylphosphine)-butane]nickel and hereinafter indicated asNi(dp-bu) n=5 Ni[Ph P-(CH -PPh which is di[1,5-bis(diphenylphosphine)-pentane]nickel and hereinafter indicated asNi(dp-pe These phosphinic complexes of nickel may be prepared bytheprocess described in Inorganic Chem. 5, 1966-1968, by CR. Van Hecke andW. Horrocks.

The isomerization of the 2-methyl-3-butene-nitrile proceeds as follows:

CHFCH-GH-CN T CHs-CH=CHCHz-CN [2-methyl-3-butene-nitrlle(2M43BN)3-pentene-nltrile(3PN)] and as already mentioned is effected in theabsence of a solvent, at normal pressure, and at temperatures between 50C and 150 C, using the catalysts described herein.

Preferably, the mixture is refluxed for a period of time ranging fromminutes to 150 minutes.

The molar ratio between the nickel complex and 2-methyl-3-butene-nitrile is from 1:100 to 111,000.

After the reaction has been completed, the crude reaction product,separated from the catalyst, can be recovered by known methods, such asby distillation and chromatography in vapor phase.

The following examples are given to illustrate the invention and are notintended to be limiting.

EXAMPLE 1 0.49 g (0.54 mM) of Ni(dp-bu) and 10 g 120 mM) of2M-3BN wereintroduced into a cc glass reactor, under an inert gas atmosphere.

The mixture was reflux heated under stirring for 1% hours, during whichtime the temperature rose from 128 to 138 C. The mixture was then cooledand discharged.

The crude reaction product, separated from the catalyst, and analyzed bygas-chromatographic analysis, contained:

71.4 percent of cis and trans 3-pentene-nitrile 12.0 percent of cis2-methyl-2-butene-nitrile 1 1.0 percent of transZ-methyl-Z-butene-nitrile The remaining mixture consisted of unreacted2- methyI-S-butene-nitrile and-of cis and trans 2-pentenenitrile.

EXAMPLE 2 0.25 g (0.28 mM) of'Ni(dp-bu) and 10 g mM) of 2M-3BN wereintroduced into a 50 cc glass reactor, under an inert gas atmosphere.

The mixture was reflux heated under stirring for 1% hours at atemperature comprised between 128 and C, then cooled and discharged.

The crude reaction product, separated from the catalyst, and analyzed bygas-chromatography, contained:

74.25 percent of cis and trans 3-pentene-nitrile 1 1.77'percent of cisZ-methyl-Z-butene-nitrile 7.6 percent of trans Z-methyl-2-butene-nitrileEXAMPLE 3 0.25 g (0.28 mM) of Ni(dp-bu) and 10 g (120 mM) of2M-3BN wereintroduced into a 50 cc glass reactor, under an inert gas atmosphere.

The mixture was reflux heated under stirring for 1 hour at a temperatureranging from 128 to 139 C, and then cooled and discharged.

The crude reaction mixture, separated from the catalyst, and analyzed bygas-chromatography, was found to contain: 1

75 .21 percent of 3-pentene-nitrile 1 1.02 percent of cis2-methyl-2-butene-nitrile 7.08 percent of transZ-methyl-Z-butene-nitrile.

EXAMPLE 5 0.20 g (0.22 mM) of Ni(dp-prh, and

g 120 mM) of2M-3BN were introduced into a 50 cc glass reactor, under aninert gas atmosphere.

The mixture was reflux heated under stirring for IV /2 hoursat atemperature comprised between 128 to l39.5 C, then cooled anddischarged.

The crude liquid product, separated from the catalystand analyzed bygas-chromatography, con

tained:

73.23 percent of 3-pentene-nitrile 9.02 percent of cis2-methyl-2-butene-nitrile 10.68 percent of trans2-methy1-2-butene-nitrile.

The remaining" liquid consisted of unconverted 2-methyl-3-butene-nitrile and of cis and trans 2pentenenitrile.

EXAMPLE 6 EXAMPLE 7 0.27 g (0.29 mM) of Ni(dp-bu) and 10 g 120 mM)of2M-3BN were introduced into a 50 cc glass reactor, under an inert gasatmosphere.

lt was heated under stirring for 1 hour and minutes, keeping thetemperature constant at 128 C, then cooled and discharged.

The crude reaction. product, separated from the catalyst and analyzed bygas-chromatography, contained:

79.5 percent of cis and trans 3-pentene-nitrile 8.78 percent of cisZ-methyI-Z-butenemitr'ile 6.24 percent of trans2-methyl-Z-butene-nitrile.

The remaining mixture consisted of unreacted 2- methyl-3-butene-nitrileand of cis and trans 2-pentenenitrile.

It will be apparent that changes in details may be made in practicingthe invention, without departing from its spirit. Therefore, we intendto include,in the scope of the appended claims, all such modificationsas will beobvious to those skilled in the art from the description andworking examples given herein.

We claim:

1. A process for preparing 3-pentenenitrile by isomerization of2-methyl-3-butene-nitri1e, characterized in that the isomerizationreaction is carried out in the absence of solvent, at normal pressure,at a temperature of from 50 C to C, for a period of time of from 15minutes to 150 minutes, and in the presence of a catalyst consisting ofa nickel complex having the general formula Phz Phz (moi :Ni B0112). PhzP g Pin I wherein Ph represents the phenyl group and n represents awhole number and is 3 or 4, and being further characterized in that themolar ratio between the nickel complex and the 2-methyl-3-butene-nitrileis from 1:100to 1:1,000.

2. The process according to claim 1, further characterized in that thecatalyst is di[ l,3-bis(diphenylphosphine)-propane] nickel.

3. The process according to claim 1, further characterized in that thecatalyst is di[1,4-bis(diphenylphosphine )-butane] nickel.

2. The process according to claim 1, further characterized in that thecatalyst is di(1,3-bis(diphenylphosphine)-propane) nickel.
 3. Theprocess according to claim 1, further characterized in that the catalystis di(1,4-bis(diphenylphosphine)-butane) nickel.